Interference Suppression Filter Weights for Symbol Timing

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Solution Overview

Problem

In wireless communication systems, increasing interference affects a receiver's ability to maintain accurate symbol timing, particularly in GSM, GPRS, and EDGE systems, as existing methods are sensitive to multi-path interference and require complex channel estimation and compensation filtering.

Innovation Solution

A method and receiver configuration that generate multiple timing hypotheses for a burst of symbols, calculate weights for an interference suppression filter, and select the best hypothesis based on a selection criteria to filter and decode the symbols, employing single antenna interference cancellation techniques to improve signal clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional channel estimation and compensation filtering methods are used, then interference suppression is attempted, but the system becomes sensitive to multi-path interference and requires complex channel estimation

Engineering Contradiction:
Improveinterference suppressionVSAvoidchannel estimation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The received signal is segmented into multiple segments corresponding to different timing hypotheses. Each segment is processed independently through the interference suppression filter with different weight sets, allowing the system to handle timing uncertainty without requiring complex overall channel estimation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the filter weights parameter based on different timing hypotheses rather than attempting to estimate the full channel response. By adjusting weights according to hypothesized timing positions, the system suppresses interference without complex channel estimation

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple timing hypotheses are generated and processed, then symbol timing accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvesymbol timing accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The signal processing is segmented into parallel paths, each handling one timing hypothesis. This allows timing accuracy to be improved through multiple hypotheses while computational complexity is managed by processing each hypothesis independently with simple filter operations rather than complex joint processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system generates multiple timing hypotheses (excessive action) to ensure accurate timing detection, but applies partial processing by using simplified interference suppression filtering for each hypothesis rather than full channel estimation, balancing accuracy with computational feasibility

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If interference suppression filtering is applied, then signal clarity is improved, but the system requires accurate timing information which is degraded by interference

Engineering Contradiction:
Improvesignal clarityVSAvoidtiming information accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by generating multiple timing hypotheses and preparing corresponding filter weight sets before actual interference suppression. This allows the filtering to proceed with anticipated timing information rather than requiring perfectly accurate timing to be known in advance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by evaluating the results of interference suppression for each timing hypothesis and selecting the hypothesis that produces the best signal quality. This feedback mechanism allows the system to recover accurate timing information even when initial timing is degraded by interference

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2324608B1Enhanced geran receiver using channel input beamforming
Publication Date: 2012.02.29 QUALCOMM INC
  • EP2324608B1 patent drawingFigure 1
  • EP2324608B1 patent drawingFigure 2
  • EP2324608B1 patent drawingFigure 3

AI summary

A method for suppressing interference in a wireless communication is provided. The method comprises receiving a burst of symbols, generating a plurality of timing hypotheses for the burst of symbols, and calculating, for each timing hypothesis, a plurality of weights for an interference suppression filter based upon a subset of the burst of symbols. The method further comprises, for each timing hypothesis, filtering the subset of the burst of symbols using the interference suppression filter with the corresponding plurality of weights, and selecting one of the plurality of timing hypotheses corresponding to a selection criteria. The method further comprises equalizing and decoding the filtered burst of symbols based upon the selected one of the plurality of timing hypotheses.